Protective Vehicle Battery Cage and Method of Making a Battery Cage

ABSTRACT

A cage assembly is provided to protect a battery pack in a vehicle. The cage assembly includes a top sub-assembly and a bottom sub-assembly that are secured together to protect the battery pack. U-shaped frames and base frames are connected together by tubular members.

TECHNICAL FIELD

This disclosure relates to a cage for attaching a battery pack to avehicle that protects the battery pack in the event of a collision andalso facilitates servicing the battery pack.

BACKGROUND

Battery cells for Battery Electric Vehicles (BEV), Hybrid ElectricVehicles (HEV) and Partial Hybrid Electric Vehicles (PHEV) are packagedin locations that are spaced away from crash zones to minimized any riskof damage during a collision event.

The tunnel that runs longitudinally along the middle of the floor may bea suitable package space for the battery because it is spaced away fromthe extremities of the vehicle. Under floor packaging of a typicalbattery pack may include cells arranged longitudinally and transverselyin the vehicle. The entire battery pack may be housed within the tunnelslaid out longitudinally and transversely in the floor of the vehicle.The area under the tunnels is a relatively a safe zone for the batterycells and performs well in full frontal and rear barrier crash tests.

However, in side crashes Moving Deformable Barrier (MDB) and Side Polecrash tests the vehicle has a tendency to bend and wrap around theimpacting barrier or pole causing the tunnel to collapse laterally. Thefloor wraps around the pole and forces the tunnel to collapse on itselfsince the body side and underbody do not provide sufficient resistance.As a result of the tunnel collapsing, battery cells can suffer damage insuch a crash mode.

Strengthening the rocker, the cross members and underbody do not provideeffective and weight efficient protection for the battery cells in thetunnel space. Up gauging of all underbody structural componentsincluding the tunnel, cross-members, and adding tunnel reinforcementsand bulk heads can mitigate tunnel collapse to some extent. However,resulting weight penalty generally out-weighs the benefits and does notprovide an acceptable solution.

This disclosure is directed to solving the above problems and otherproblems relating to securing a battery pack in a BEV, HEV or PHEV typeof vehicle.

SUMMARY

According to one aspect of this disclosure, a cage is provided for abattery pack. The cage comprises a top sub-assembly that includes afirst plurality of tubes that are spaced apart and a plurality of spacedinverted U-shaped frames that have a frame height corresponding to theheight of one or more batteries. The cage also comprises a lowersub-assembly including a second plurality of tubes that are spaced apartand a plurality of spaced frames having a height that is less than theframe height, and is assembled to the top sub-assembly.

According to other aspects of this disclosure relating to the cage for abattery pack, the inverted U-shaped frames may define a plurality ofopenings that each receive one of the first plurality of tubes. Thespaced frames of the lower sub-assembly each may define a plurality ofopenings that each receive one of the second plurality of tubes. Thespaced inverted U-shaped frames may have upper feet that extendoutwardly from the lower ends of the U-shaped frames and the spacedframes of the lower sub-assembly may each have lower feet that extendoutwardly from the spaced frames at locations corresponding to the upperfeet to facilitate assembling the upper feet to the lower feet withfasteners. The lower sub-assembly may further comprise a pan that isframed by a portion of the tubes and the spaced frames of the lowersub-assembly.

According to additional aspects of this disclosure, the first pluralityof tubes may include a first set of longitudinally extending tubes and afirst set of transversely extending tubes. The second plurality of tubesmay include a first set of longitudinally extending tubes and a secondset of transversely extending tubes. The first set of longitudinallyextending tubes and the second set of longitudinally extending tubes maybe assembled to a longitudinally extending tunnel in a floor pan of avehicle and the first set of transversely extending tubes and the secondset of transversely extending tubes may be assembled to a transverselyextending tunnel formed in the floor pan of the vehicle.

The cage for a battery pack of a vehicle is provided in combination withthe battery pack and further comprises a plurality of battery cells. Thetop sub-assembly and lower sub-assembly are assembled together onopposite sides of the battery cells. The combination may furthercomprise a damper that comprises a foam pad disposed between the batterycells and the top sub-assembly and/or lower sub-assembly.

According to other aspects of this disclosure as it relates to a methodof making a cage for a battery pack of a vehicle, the method maycomprise assembling a first plurality of spaced tubes that and aplurality of spaced inverted U-shaped frames to from a firstsub-assembly, and assembling a second plurality of spaced tubes and aplurality of spaced frames to form a second sub-assembly. The firstsub-assembly and the second sub-assembly are assembled together toenclose the battery pack.

According to other aspects of the method, the first plurality of spacedtubes may be welded to the plurality of spaced inverted U-shaped framesand the second plurality of spaced tubes may be welded to the pluralityof spaced frames. The first and second plurality of spaced tubes may beextruded. The U-shaped frames and spaced frames may be extruded.Alternatively, the U-shaped frames and the spaced frames may be formedby casting. The method of making a cage for a battery pack claim mayfurther comprise bolting the first sub-assembly to the secondsub-assembly.

The method of making a cage for a battery pack may further compriseinserting a damper between the battery pack and the second sub-assembly

The above aspects of the disclosure and other aspects will be more fullydescribed below in the detailed description of the illustratedembodiments and in view of the attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a fragmentary perspective view of a battery cage enclosing aplurality of battery cells in a vehicle that is shown in phantom.

FIG. 2 is a perspective view of a cage and a battery pack.

FIG. 3 is a perspective view of a top sub-assembly of the cage for abattery pack.

FIG. 4 is a perspective view of a lower sub-assembly of a cage for abattery pack.

FIG. 5 is a perspective view of the assembled cage for a battery pack.

FIG. 6 is a diagrammatic cross-sectional view of a battery pack disposedon a isolator.

DETAILED DESCRIPTION

A detailed description of the illustrated embodiments of the presentinvention is provided below. The disclosed embodiments are examples ofthe invention that may be embodied in various and alternative forms. Thefigures are not necessarily to scale. Some features may be exaggeratedor minimized to show details of particular components. The specificstructural and functional details disclosed in this application are notto be interpreted as limiting, but merely as a representative basis forteaching one skilled in the art how to practice the invention.

Referring to FIG. 1, a vehicle 10 is shown with a battery pack 12. Thebattery pack 12 is partially enclosed by a cage assembly 16. The cageassembly 16 is provided to protect the battery pack 12 in the event thatthe vehicle 10 is involved in a collision. The cage assembly 16 preventsimpact loads from being transferred directly to the battery pack 12. Thecage assembly 16 protects the battery pack 12 from deformation due tocrash loading.

Referring to FIG. 2, the battery pack 12 is shown in greater detail asit is disposed within the cage assembly 16. The battery pack 12 is madeup of a plurality of individual battery cells 18. The battery cells 18may be arranged in a longitudinal stack 20 that extends in alongitudinal vehicle direction. The longitudinal stack 20, as shown,includes a portion that has a double stack 22 of battery cells 18 and asingle stack 24 of batteries 18. A transverse stack 26 of battery cells18 is also shown in FIG. 2 that extends in the transverse vehicledirection. The transverse stack 26 intersects the longitudinal stack 20.It should be understood that the battery pack 12 and cage assembly 16may be arranged with a different number of battery cells 18 or in adifferent arrangement depending upon the packaging space availablewithin a given vehicle design.

Referring to FIG. 3, a top sub-assembly 30 of the cage assembly 16 isillustrated. The top sub-assembly 30 includes a plurality of U-shapedframes 32 in the single stack 24 area of the cage assembly 16. Aplurality of double stacked U-shaped frames 34 are also provided as partof the longitudinal stack 20 that includes the double stack 22 ofbattery cells 18. The U-shaped frames 32, 34 each include a pair ofupper feet 36 on the lower ends of the U-shaped frames. The cageassembly 16 may be formed using U-shaped frames 32, 34 that are formedas aluminum extrusion or magnesium castings. Alternatively, carbon fiberreinforced plastics may be used to further reduce the weight of theU-shaped frames 32 and 34.

Holes 38 are provided in the upper feet 36 to receive fasteners (notshown). Tubes 40 are inserted into top holes 42 that are provided in theU-shaped frames 32 and the double stacked U-shaped frames 34.Intermediate holes 44 are provided at an intermediate location on thedouble stacked U-shaped frames 34.

Referring to FIG. 4, a bottom sub-assembly 46 is illustrated thatincludes a plurality of base frames 48 that are interconnected bytubular segments 50. The tubes 40, 50 may be formed as extruded tubes oras seamless aluminum tubing. The tubular segments 50 may stem betweentwo base frames 48 or through six or more base frames 48, as shown inFIG. 4. Holes 52 that receive the tubular segments 50 are provided ineach of the base frames 48. The tubes 40, 50 are preferably welded intothe holes 38, 52 by MIG welding or other joining techniques. A pair oflower feet 54 are provided on each of the base frames 48. A hole 56 fora fastener (not shown) is provided in each of the lower feet 54.

Referring to FIG. 5, the cage assembly 16 is shown with the topsub-assembly 10 shown in FIG. 3 being assembled to the bottom of thesub-assembly 46 shown in FIG. 4. The upper feet 36 are attached to thelower feet 54 by fasteners that are inserted through the hole 38 in theupper feet 36 and the holes 56 provided in the lower feet 54. The lowersub-assembly 46 can be constructed with a framed pan that holds thebattery pack and allow the entire battery pack to be removed forservicing.

Referring to FIG. 6, a damper 60 is shown diagrammatically, the batterypack 12 is supported on the damper 60. The damper 60 includes a foamlayer 62 that is flanked on upper and lower sides by rigid layer 64. Thedamper 60 may be supported on a bottom pan 66 that is disposed betweenthe damper 60 and the base frames 48. The U-shaped frame 32 is shownassembled to the base frame 48 to enclose the battery pack 12. Thedamper 60 prevents impact loads from being transferred directly to thebattery pack. The cage assembly 16 prevents adverse deformation of thebattery pack due to crash loading. The battery pack 12 can be isolatedby the damper 60 to mitigate the effects of any harmful suddenacceleration or deceleration of the battery pack when the vehicle isimpacted.

A bottom sub-assembly 46 may be removed from the top sub-assembly 30 inthe event that it is necessary to service the battery cells 48. The topsub-assembly 30 may be secured to the vehicle 10 on the bottomsub-assembly 46 is secured under the top sub-assembly 30. The fastenerssecuring the bottom sub-assembly 46 to the top sub-assembly 30 may beremoved and the bottom sub-assembly 46 may be removed to either provideaccess to the battery cells 18 or to allow the battery pack 12 to beremoved from the vehicle 10 while either leaving the top sub-assembly 30attached to the vehicle 10 or the top sub-assembly may be removed withthe bottom sub-assembly 46 with the battery pack 12

The cage assembly 16 is a lightweight space frame structure that isintended to protect a battery electric vehicle, hybrid electric vehicle,or partial hybrid electric vehicle battery cells in vehicle crashes.

While exemplary embodiments are described above, it is not intended thatthese embodiments describe all possible forms of the disclosed apparatusand method. Rather, the words used in the specification are words ofdescription rather than limitation, and it is understood that variouschanges may be made without departing from the spirit and scope of thedisclosure as claimed. The features of various implementing embodimentsmay be combined to form further embodiments of the disclosed concepts.

What is claimed is:
 1. A cage for a battery pack comprising: a topsub-assembly includes a first plurality of tubes that are spaced apartand a plurality of spaced inverted U-shaped frames that have a frameheight corresponding to a battery height; and a lower sub-assemblyincluding a second plurality of tubes that are spaced apart and aplurality of spaced frames having a height that is less than the frameheight, and is assembled to the top sub-assembly.
 2. The cage for thebattery pack of claim 1 wherein the inverted U-shaped frames define aplurality of openings that each receive one of the first plurality oftubes.
 3. The cage for the battery pack of claim 1 wherein the spacedframes of the lower sub-assembly each define a plurality of openingsthat each receive one of the second plurality of tubes.
 4. The cage forthe battery pack of claim 1 wherein the spaced inverted U-shaped frameshave a pair of upper feet that extend outwardly from a pair of lowerends of the U-shaped frames, and wherein the spaced frames of the lowersub-assembly each have lower feet that extend outwardly from the spacedframes at locations corresponding to the upper feet, and wherein theupper feet are assembled to the lower feet with fasteners.
 5. The cagefor the battery pack of claim 1 wherein the lower sub-assembly furthercomprises a pan that is framed by a portion of the tubes and the spacedframes of the lower sub-assembly.
 6. The cage for the battery pack ofclaim 1 wherein the first plurality of tubes includes a first set oflongitudinally extending tubes and a first set of transversely extendingtubes, and the second plurality of tubes includes a first set oflongitudinally extending tubes and a second set of transverselyextending tubes, wherein the first set of longitudinally extending tubesand the second set of longitudinally extending tubes are assembled to alongitudinally extending tunnel in a floor pan of a vehicle and thefirst set of transversely extending tubes and the second set oftransversely extending tubes are assembled to a transversely extendingtunnel formed in the floor pan of the vehicle.
 7. The cage for thebattery pack of claim 1 wherein the U-shaped frames of the topsub-assembly and the spaced frames of the lower sub-assembly arecastings.
 8. The cage for the battery pack of claim 1 wherein theU-shaped frames of the top sub-assembly and the spaced frames of thelower sub-assembly are extruded parts.
 9. The cage for the battery packof claim 1 in combination with the battery pack further comprises aplurality of battery cells, and wherein the top sub-assembly and lowersub-assembly are assembled together on opposite sides of the batterycells.
 10. The cage for the battery pack in combination with the batterypack of claim 9 further comprising a damper disposed between the batterycells and the top sub-assembly and lower sub-assembly, wherein thedamper is a resilient foam pad.
 11. A method of making a cage for abattery pack of a vehicle comprising: assembling a first plurality ofspaced tubes that and a plurality of spaced inverted U-shaped frames tofrom a first sub-assembly; and assembling a second plurality of spacedtubes and a plurality of spaced frames to form a second sub-assembly;and assembling the first sub-assembly and the second sub-assemblytogether to enclose the battery pack.
 12. The method of making the cagefor the battery pack of claim 11 further comprising: welding the firstplurality of spaced tubes to the plurality of spaced inverted U-shapedframes; and welding the second plurality of spaced tubes to theplurality of spaced frames.
 13. The method of making the cage for thebattery pack of claim 11 further comprising: extruding the first andsecond plurality of spaced tubes.
 14. The method of making the cage forthe battery pack of claim 11 further comprising: extruding the U-shapedframes; and extruding the spaced frames.
 15. The method of making thecage for the battery pack of claim 11 further comprising: casting theU-shaped frames; and casting the spaced frames.
 16. The method of makingthe cage for the battery pack of claim 11 further comprising: boltingthe first sub-assembly to the second sub-assembly.
 17. The method ofmaking the cage for the battery pack of claim 11 further comprising:inserting a damper between the battery pack and the second sub-assembly.